there are many approaches for solving variety combinatorial optimization problems (np-compelete) that devided to exact solutions and approximate solutions. exact methods can only be used for very small size instances due to their expontional search space. for real-world problems, we have to employ approximate methods such as evolutionary algorithms (eas) that find a near-optimal solution in a r...

the thesis has been arranged into five chapters and mainly concerned with the baer-invariant of groups which is the generalization of the schur-multiplier with respect to the variety of groups. chapter one is devoted to collect some notation and background information which are needed in the next chapters. its also contains some important statements which will be generalized in this thesis. cha...

abstract:assume that y is a banach space such that r(y ) ? 2, where r(.) is garc?a-falset’s coefficient. and x is a banach space which can be continuously embedded in y . we prove that x can be renormed to satisfy the weak fixed point property (w-fpp). on the other hand, assume that k is a scattered compact topological space such that k(!) = ? ; and c(k) is the space of all real continuous ...

from 1950s onward, new theories and critical approaches burgeoned across humanities. these theories were context-oriented; as a result, the analysis of discursive practices gained significance. thus, social, political, historical and cultural discourses that have been hitherto marginalized and considered inferior to literary texts, were introduced as important texts to be analyzed by critics. o...

the treatment of in completely formed pulpless teeth has presented considrable problems. these teeth have wide open apexes and the walls of the root canal diverge toward the apical tissues. mechanical preparation cannot be done in the normal manner beacause of the large initial size and the taper of apical part of the canal , a mechanical stop cannot be produced at the apex of the canal and , t...

‏‎‏‎utopia has, for four centuries, accompanied that hope of progress and that striving for betterment. it now straggles against a widespread sense that this has been an illusion, or an impossible dream. the utopian idea can never entirely disappear, but utopia as a form of the social imagination has clearly weakened. if it cannot instill its vision in the public consciousness, the consequences...

this thesis basically deals with the well-known notion of the bear-invariant of groups, which is the generalization of the schur multiplier of groups. in chapter two, section 2.1, we present an explicit formula for the bear-invariant of a direct product of cyclic groups with respect to nc, c>1. also in section 2.2, we caculate the baer-invatiant of a nilpotent product of cyclic groups wuth resp...

in the past couple of decades sociocultural theory of sla and its implications in efl contexts have attracted attentions of research circles worldwide and aroused some controversies. firth and wagner (1997) have questioned the principles of the cognitive view which gives importance to mental constructs in favor of sociocultural view which highlights social and contextual constructs. but if soci...

testing plays a vital role in any language teaching program. it allows teachers and stakeholders, including program administrators, parents, admissions officers and prospective employers to be assured that the learners are progressing according to an accepted standard (douglas, 2010). the problems currently facing language testers have both practical and theoretical implications but the first i...

there are two major theories of measurement in psychometrics: classical test theory (ctt) and item-response theory (irt). despite its widespread and long use, ctt has a number of shortcomings, which make it problematic to be used for practical and theoretical purposes. irt tries to solve these shortcomings, and provide better and more dependable answers. one of the applications of irt is the as...